Each of the shuttle’s two solid rocket boosters was made up of four sections, each of which was held together by a tang on one section that fit into a coupler on the other. A rubber O-ring and putty made of zinc chromate filled with asbestos formed a seal at the join. A second ring acted as a backup. When the solid rocket boosters fired the combustion of the propellant would produce tremendous heat and pressure.
At the same time, the million pounds of thrust from the liquid-fuel rockets would create enormous forces and bend the solid rocket boosters slightly. Only the O-ring would keep hot gases from blowing out of the seal. The Challenger had been sitting on its launching pad for 38 days prior to launch. During that time, 17.8 cm (7 in.) of rain had come down. No one was sure how these conditions would affect the rings.
In the end the decision was made to launch anyway, with disastrous consequences. Cold weather combined with a defect in the solid rocket booster were to blame for the astronauts’ deaths.
If you like the list you see here, you can find over 50 more events listed in her new book.
The following list was contributed by: Laura LeeAuthor of Blame It on the Rain
